1. Field of the Invention
This invention relates to a display and a labeled article. This invention relates to, for example, a display which can be used for forgery-prevention of articles such as cards, securities and brand-name products and which displays an image by utilizing light-scattering, and to a labeled article including it.
2. Description of the Related Art
Generally, a pattern for displaying an image by light-scattering (hereinafter called a light-scattering pattern) is formed by subjecting a surface of a substrate to a relief-processing. The relief-processing method includes, for example, a method of etching a substrate, a method of roughening a surface of a substrate with a chemical, a method of forming relief on a surface of a substrate using an EB writer, or the like.
Among these method, according to the method utilizing etching and the method using a chemical, it is difficult to make a density of recesses and/or protrusions in a certain fine region different from that in another fine region, on a surface where the recesses and/or protrusions are to be formed. It is therefore difficult to make the degrees of scattering in those regions different from each other by controlling the densities of the recesses and/or protrusions. On the other hand, if the EB writer is used, the densities and shapes of recesses and/or protrusions to be formed in the fine regions can be controlled arbitrarily.
Jpn. Pat. Appln. KOKAI Publication No. 5-273500 describes a display on which a diffraction grating pattern and a light-scattering pattern are formed in the same surface using an EB writer. This display has the following effects.
(a) Since display does not rely on diffracted light alone, restrictions on observation conditions are small.
(b) Since the scattered light is also used for the display, an iridescent appearance is not the only impression that the image offers.
(c) Since both the diffraction grating pattern and the light-scattering pattern are constituted by the recesses and/or protrusions, those patterns can be formed by embossing and the alignment between those patterns is unnecessary.
However, a relief-type diffraction grating can be formed with relative ease by laser facilities, etc. In addition, a visual effect of the light-scattering pattern included in the above display can be obtained from, for example, a printed layer containing transparent particles and transparent resin having a refractive index different from that of the transparent particles. For this reason, the forgery-prevention effect of this display is not always considered sufficient.